5G Waveform Generation & Analysis Testbed, Reference Solution
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SOLUTION BROCHURE 5G Waveform Generation & Analysis Testbed, Reference Solution Introduction Flexibility required for 5G research - waveform generation and analysis One of the biggest challenges faced by today’s 5G researchers is the number and variety of waveforms, frequencies, and bandwidths being investigated. This includes waveforms at frequencies below 6 GHz, and at microwave and millimeter-wave frequencies which may involve wide bandwidths. To address the multitude of possible scenarios, a flexible test environment is critical for this stage of 5G signal generation and analysis research. 5G Waveform Generation & Analysis Test Challenges Flexibility is essential in 5G research. It enables “what if ?” analyses to be performed during evaluation of early concepts and potential 5G waveforms, using a variety of modulation schemes at many different frequencies and modulation bandwidths. The risk of potentially choosing the wrong path further reinforces the need for flexibility, especially in the form of signal creation and signal analysis tools that enable rapid changes in direction as strong waveform candidates emerge in the evolution of 5G. As developers conduct experiments, a highly flexible testbed will enable them to evaluate proposed waveforms with prototype algorithms and hardware. It will also make it possible to quickly and easily transition between what-if scenarios in simulation and actual testing of the prototype algorithms and hardware. More specifically, flexibility is needed in three key areas of 5G research and early testing: – Generating and analyzing 3GPP 5G NR and multi-format waveforms with high fidelity – Supporting a wide range of modulation bandwidths, from 100 MHz to over 5 GHz – Supporting a wide range of frequency bands, from RF to centimeter-wave to millimeter-wave Find us at www.keysight.com Page 2 5G 3GPP NR Waveform Generation and Analysis (28 - 39 GHz) To help address these test challenges, the 5G waveform generation and analysis reference solution combines hardware, software and measurement expertise providing the essential components of a flexible 5G waveform generation and analysis test platform. The reference solution enables engineers and researchers to generate and analyze a variety of 3GPP 5G NR waveforms at RF, centimeter-wave, and millimeter-wave frequencies with modulation bandwidths of up to 2 GHz, with an emphasis on 5G 3GPP NR activity in the 28 GHz and 37 - 39 GHz bands. The M9384B VXG Microwave Vector Signal Generator combined with Signal Studio software enable a variety of standards compliant and custom 3GPP 5G NR waveforms. The dual channel capability enables a variety of uses cases including: generating spatially multiplexed signals, creating low power level wanted signals and high power interfering signals, and creating phase coherent signals for use in evaluating amplitude and phase shifts in phased array antenna systems with real-world modulated signals. For signal demodulation and analysis, 89600 VSA software can be used either inside the simulation software, or on a signal analyzer, oscilloscope or PC controlling a variety of instruments or digitizers. Figure 1 below shows a common arrangement of the software and hardware elements and Figure 2 shows a combination of Keysight Technologies, Inc. hardware and software for a flexible 5G generation and analysis testbed. Ref Ref plane plane Load S-parameters of Component Load S-parameters of test fixture into generator test fixture into analyzer device to move reference plane to move reference plane under test (DUT) to DUT interface to DUT interface 5G waveform Known good transmitter and receiver system to measure true DUT performance Figure 1. The 5G testbed provides combinations of hardware and software, giving the researcher flexibility and accuracy needed to explore 5G technologies, and then validate 5G designs. Find us at www.keysight.com Page 3 Figure 2. This 5G Testbed configuration supports 3GPP NR signal creation up Figure 4. This 5G testbed configuration enables signal generation and analysis to 44 GHz with traditional bench top spectrum analysis up to 50 GHz. Both of signals between 50 GHz and 110 GHz with very wide bandwidths in excess of instruments support integrated 1 GHz bandwidth capability. +5 GHz. The M8195A arbitrary waveform generator provides direct IF signals to the external mixer, while the N5183B MXG microwave analog signal generator provides the LO for up conversion to mmW frequencies. The N9041B UXA signal analyzer can directly digitize signal bandwidths up to 1 GHz for analysis. The UXA wideband IF output enables +5 GHz bandwidth signal to be analyzed with an oscilloscope. Features Benefits Pre-5G and 5G new radio candidate waveforms Quickly evaluate designs for emerging waveforms to gain insights and reduce risk Scalable modulation bandwidths and frequency bands Provides flexibility to adapt as 5G evolves- reduce risk of choosing the wrong path Factory calibrated at all frequencies, amplitudes, and bandwidths Evaluate true performance of your device under test with metrology grade test equipment Find us at www.keysight.com Page 4 Reference Solution Configuration Signal creation configuration For pre-5G and 5G new radio signals in the 28 and 39 GHz bands, the new M9384B VXG Microwave Vector Signal Generator directly offers 1% EVM up to 2 GHz bandwidths, without external heads or components. Above 2 GHz bandwidths, an external AWG is required. The M8190A AXIe AWG can operate with 14-bit resolution at up to 8 GSa/s or 12-bit resolution up to 12 GSa/s. It offers 5 GHz of analog bandwidth. For even higher modulation bandwidths, the M8195A (discussed later) may be considered. For signal generation above 44 GHz, compact upconverters are available from Keysight and Virginia Diodes, Inc (50 to 110 GHz). MXG microwave analog signal generators provide the LOs for the mmWave upconverters. These are discussed in the next section. The N7631C Signal Studio pro for 5G NR, N7630C for Pre-5G, and N7608C for custom modula- tion are flexible software tools for quickly creating a variety of standards compliant and custom waveforms for evaluating DUT characteristics over a wide range of signal configurations. The parameterized graphical user interfaces (GUI) make it easy to quickly create 5G NR, pre-5G, custom OFDM, and custom IQ waveforms. VSA setup files can be saved for quickly recalling configurations in the 89600 VSA software. The Keysight 89600 VSA software is used for in-depth demodulation and analysis insights. Keysight signal generators and signal analyzers are calibrated over frequency, amplitude, and modulation bandwidth to enable metrology grade measurements ensuring you can see the true performance of your DUT rather than the test equipment. However, at wider modulation bandwidths and higher carrier frequencies the test fixturing between the instrument and the DUT can start to have a significant impact on the amplitude and phase response across the signal bandwidth. Typical test fixturing includes, adapters, cables, couplers, combiners, and even amplifiers. The generators and analyzers enable de-embedding of the test fixture by importing the S-parameters of the text fixture, effectively moving the calibration plane from the instrument to the input/output of the DUT. The S-parameters can be measured with a network analyzer or may be directly available from the manufacturer of the test fixture component. Figure 3. The M9384B VXG Microwave Vector Signal Generator and N7630C Signal Studio software are used for creating a variety of 3GPP 5G NR signals. Find us at www.keysight.com Page 5 Signal analysis configuration For vector signal analysis, the UXA (N9040B 50 GHz or N9041B 110 GHz) can directly demodulate up to 1 GHz bandwidths using option H1G. For backhaul and higher mmW bands with wider bandwidths up to 5 GHz, the N9041B can be used as a precision downconverter to an S-Series Infiniium oscillioscope, which samples the IF. For the ultimate in bandwidth, a high performance oscilloscope can be used to digitize the signal directly at RF and mmWave frequencies. For example, the Infiniium UXR-Series scopes feature sample rates up to 256 GHz with 10-bits of vertical resolution, enabling high fidelity measurements similar to a spectrum analyzer. Additionally, the oscilloscope is available in four channel versions for multi-channel measurements like MIMO spatial multiplexing measurements. Since the oscilloscope is natively phase coherent, it makes measuring DUTs like phased array antennas and chipsets simple and fast. Figure 4. Wideband smart mixer, UXA signal analyzer, UXR-Series oscilloscope and 89600 VSA Software Find us at www.keysight.com Page 6 Digitized IQ Samples for 89600 VSA SW UXR-Series Oscilloscope PC for running Signal Studio signal M8195A creation SW & 89600 VXA signal 65 GSa/s AWG analysis SW Note: The controller in the M8195A or the UXR can also be used to run the SW Create signals with up to +10 GHz of BW The UXR can directly digitize signals of any frequency/ VDI Upconverter bandwidth up to 110 GHz Device OR under test (DUT) DSOS804A S-Series VDI models available with N9041B oscilloscope frequency coverage from 110 GHz UXA 50 GHz to 110 GHz N5183B MXG low phase noise LO UXA downconverts to 5 GHz BW IF which is digitized by the S-Series Scope OR E8257D PSG low phase noise LO Figure 5. Example hardware configuration for millimeter-wave waveform generation and analysis at 73 GHz. A simple block diagram of a 73 GHz configuration is shown in Figure 5 that can be used for 5G RF, microwave and millimeter-wave signal generation and analysis. The hardware configuration can be altered, to address the actual frequencies, bandwidths and waveforms of interest. Figure 5 includes the AWG previously described, along with a Virginia Diodes upconverter, which upconverts the signal to 73 GHz. A low phase noise local oscillator (MXG or PSG) drives the millimeter-wave upconverter. Optionally, a waveguide amplifier, variable attenuator, and bandpass filter (not shown) can be added at the VDI upconverter output, to improve amplitude range and suppress out-of-band images.